Comparisons of Flame Surface Density Measurements with Direct Numerical Simulations of a lean Methane-air Flame in High-intensity Turbulence

The turbulent burning velocity of premixed flames exhibits a non-linear variation under increasing turbulence intensity of the unburned mixture. This phenomenon, known as the bending effect, has not been fully explained to date. A key aspect is the mechanism responsible for the observed departure from linearity. Experimental measurements of spherically-expanding flame kernels [Bradley et al. (2013), Proc.Combust.Inst., 34:1519–1526.] point towards local quenching as the primary mechanism of inhibition (bending). On the other hand, recent Direct Numerical Simulations of statistically-planar flames [Nivarti et al. (2017), Proc.Combust.Inst. , 36:(in press).] indicate that bending might be achieved in the absence of local quenching. The present study investigates the underlying mechanisms by comparing DNS data with experimental measurements of a lean premixed methane-air flame in high-intensity turbulence.